Luminous material



Dec. 3l, 1946. l J. R. LYNCH 2,413,459

LUMINOUS MATERIAL Filed Aug. 22.1944

ZINC SULPmnE RDHES\VE TANTINUM DIOXIDE FABR'C f r 0 /z ya@ ATTORNEYS Patented Dec. 31, 1946 LUMINOUS MATERIAL John R. Lynch, Providence, R. I., assignor to E. P. Lynch, Inc., a corporation of Rhode Island Application August 22, 1944, Serial No. 550,664

(Cl. Z50-80) 1 claim. 1

This invention relates to luminous or phosphorescent material and the application thereof to an obverse surface.

Luminous material, sometimes referred to as phosphorescent material, although there may be no phosphorous present, as it is available at the present time may be graded or classified as to certain characteristics it has by the amount of brilliance or impact it has on the eye and as to the time it will remain observable after charging by exposure to light. Some luminous material which has a brilliant afterglow will be visible for a relatively short time (usually two hours or less) whereas other materials which are not as brilliant upon sudden darkness may be observed for a much longer time (usually from two to twelve hours). The definition adopted for short and long afterglow is that set forth in the statement'by the National Bureau of Standards of Washington in a letter circular LC-6'78 of January 24, 1942.

VOne of the objects of this invention is to provide a luminescent material which will have predominantly long afterglow but will havel an initial brilliance which is stepped up to a considerable extent beyond that which is usually present in long afterglow material.

Another object of this invention is to utilize a short afterglow more brilliant material to bring up the initial brilliance of the long afterglow material.

Another object of the invention is to provide a v method by which the amount of initial brilliance may be predetermined and acquired by the amount of surface covered by one material relative to the other in the finished product.

With these and other objects in view, the invention consists of certain novel features of construction, as will be more fully described and particularly pointed out in theappended claim.

In the accompanying drawing:

Fig. 1 is a sectional View through a piece of fabric coated in accordance with this invention;

Fig. 2 is a plan View thereofL It has been found desirable to provide an initially greater brilliance for long afterglow material than is ordinarily present in such mate` rial. However, at the same time it is found that the initial brilliance provided by the short after' glow material is unnecessary. Accordingly, I have yprovided short afterglow material on the surface to be coated and then covered the entire surface including the coating of short afterglow material with the long afterglow material which is predominantly desired and I proportion the 2 area covered by the vshort afterglow material so that I will obtain substantially the effect desired.

With reference to the drawing, I have illustrated a fabric base I0 which presents a surface to which the luminous material is applied. This base has an initial coating I I thereon of titanium dioxide or some other material which will-act as a good reflector of light or ultra violet activating rays. Upon this titanium dioxide coat I provide a coating I2 of a material which will have short afterglow and which I have illustrated as in the form of a stripe extending lengthwise of the fabric. The stripe is of a width a and I find that to meet certain desired specifications the width of this stripe will be one-fourth of the Width of the space of a width b between stripes.

After this stripe of short afterglow has been applied and hardened so that there will be no mixing of the short afterglow material with the long afterglow material, I apply a coating I3 of long afterglow material which not only fills the space between the stripes I2 of short afterglow material but also covers with a thin coating the short afterglow material. In other words the long afterglow material is a coating all over the surface which is to be provided with luminescent material.

VI also apply on the under side of the fabric I0 an adhesive coating I4 so that the fabric may be positioned on a wall or at other desired locations by reason of its own adhesiveness.

' The luminescent material I2 with short afterglow'character may be any one of a variety of well-known substances such, for example as, zinc sulfide, magnesium sulde, or barium sulfide which are the better known commercially prominent materials having this characteristic. I select zinc sulde as it is less acted upon by moisture.

Material'which will have less brilliancy but,A

.which they are applied and which vehicle may later partly evaporate to cause a set of the pigments on the surface. It is important in applying these luminescent materials where one material coats or forms a layer over the other material that the rst material be set so that the pigment will not mix one with the other.

By providing a fabric as here constructed, I find that with substantially twenty minutes activation I will obtain a brilliance in the order of 2.53 microlamberts at twenty minutes after light is extinguished and of the order of 1.06 microlamberts after light has been extinguished for one hour. Thelmaterial is not hygroscopic and will meet certain U. S. Maritime Commissions specifications.

The material is useful for the in.

terior of ships in which some trouble may develop to the interior lighting, or for use where the loca- 4 tion of some object is to .become apparent in the dark.

I claim:

An article of manufacture comprising a base presenting a surface, luminescent materials of relatively longer and shorter afterglow on said surface, the material of shorter afterglow being applied in spaced areas on said surface and a coating of material of longer afterglow covering the shorter'afterglow material and the remainder of the surface area, each coating maintaining its distinction Without mingling.

JOHN R. LYNCH. 

